Medical Definition of Bacteriorhodopsin
1.
A light driven proton pumping protein (248 residues, 26 kD), similar to rhodopsin, found in purple patches in the cytoplasmic membrane of the bacterium Halobacterium halobium.
It is composed of 7 transmembrane helices and contains the light absorbing chromophore, retinal. Light absorption maxima: 568 nm (light adapted), 558 nm (dark adapted). Each photon results in the movement of 2 protons from cytoplasmic to extracellular sides of the membrane. The resulting proton gradient is used (amongst other things) to drive chemiosmotic synthesis of ATP.
This entry appears with permission from the Dictionary of Cell and Molecular Biology
(11 Mar 2008)
Lexicographical Neighbors of Bacteriorhodopsin
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